On Tue, Nov 30, 2004 at 07:15:44AM -0800, Eric Rescorla wrote: > SSL has all three of these modes, actually, so perhaps the question > you want to ask is why noone uses #3. The main argument against it is > that it's about half as fast (on the server) in the best case because > you need to do both a signature and a key exchange operation. > On the client it's *much* slower because RSA public-key encryption > is very fast (private-key decryption is much slower). >
The third mode is quite common for STARTTLS with SMTP if I am not mistaken. A one day sample of inbound TLS email has the following cipher frequencies: 8221 (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) 6529 (using TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) 186 (using SSLv3 with cipher DHE-RSA-AES256-SHA (256/256 bits)) 117 (using TLSv1 with cipher RC4-SHA (128/128 bits)) 59 (using SSLv3 with cipher RC4-SHA (128/128 bits)) 40 (using SSLv3 with cipher DES-CBC3-SHA (168/168 bits)) 28 (using TLSv1 with cipher RC4-MD5 (128/128 bits)) 16 (using SSLv3 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) 14 (using TLSv1 with cipher DES-CBC3-SHA (168/168 bits)) 1 (using SSLv3 with cipher RC4-MD5 (128/128 bits)) 1 (using SSLv2 with cipher DES-CBC3-MD5 (168/168 bits)) it is my perhaps misguided impression that the both the EDH and the DHE cipher-suites provide PFS. Is there in fact a difference between EDH and DHE? -- /"\ ASCII RIBBON NOTICE: If received in error, \ / CAMPAIGN Victor Duchovni please destroy and notify X AGAINST IT Security, sender. Sender does not waive / \ HTML MAIL Morgan Stanley confidentiality or privilege, and use is prohibited. --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]